Linear and nonlinear analysis of autonomic regulation of heart rate variability in healthy first-degree relatives of patients with schizophrenia

Abstract

The recently reported cardiac autonomic dysregulation in patients with schizophrenia is characterized by a decreased vagal and an increased sympathetic modulation. This impairment possibly contributes to the increased cardiovascular mortality rate that is up to three times higher in these patients than in general population. The aim of this study was to characterize the autonomic regulation in schizophrenia and to evidence for a genetic influence. We investigated 36 patients with schizophrenia, 36 healthy first-degree relatives and 36 healthy controls. The autonomic regulation was classified applying linear and nonlinear methods of heart rate variability analysis. Healthy relatives were compared with healthy controls matched with respect to age and gender and with patients suffering from schizophrenia. Further on, schizophrenic patients were compared with healthy controls. The results show that the autonomic regulation in healthy relatives differs significantly from healthy controls (p〈0.01) and slightly from patients. However, the most significant differences could be found between patients and healthy controls (p〈0.0001). Relatives revealed decreased heart rate variability and demonstrated an altered autonomic modulation of heart rate and similar pattern of autonomic dysfunction as patients. This autonomic impairment found in relatives might indicate an underlying disease-inherent genetic vulnerability, especially since it is known that heart rate variability is partially under genetic control.

High-resolution joint symbolic analysis to enhance classification of the cardiorespiratory system in patients with schizophrenia and their relatives

“…As a consequence, one could determine whether the possible genetic disposition will lead to an increased incidence of schizophrenia within healthy relatives and whether such a pathological development could be predicted at an earlier stage [12].…”

“…In addition to these factors, the dysregulation of the autonomic nervous system (ANS) during acute psychosis has become evident for patients with schizophrenia in studies carrying out heart rate variability (HRV) analysis. Studies applying HRV analyses found reduced vagal and increased sympathetic modulation, indicating a cardiac autonomic dysregulation in patients with schizophrenia and partly in their healthy first-degree relatives [6][7][8][9][10][11][12][13]. The pattern of autonomic dysfunction seen in patients and their relatives might indicate underlying diseaseinherent genetic vulnerability, especially as it was shown by Busjahn et al [14] that a genetic dependency of autonomic parameters (HRV) exists.…”

Joint symbolic dynamics for the assessment of cardiovascular and cardiorespiratory interactions

“…HR and SAP time series of patients with acute schizophrenia showed reduced JSDsym, increased JSDdiam and JSDshannon, indicative of impaired baroreflex control [ 77 , 78 ]. Differences in the RR and SAP word distribution matrix were also observed between schizophrenic patients, their first degree relatives and normal subjects [ 79 ]. Similarly, joint symbolic analysis of respiratory interval and RR interval time series showed increased complexity in patients with schizophrenia [ 77 ] and first degree relatives [ 54 ] compared with normal subjects.…”

The Cardiorespiratory Network in Healthy First-Degree Relatives of Schizophrenic Patients

“…Studies investigating HRV generally showed an altered sympathovagal balance pointing to dysregulation of heart rate for schizophrenic patients and partially their first-degree healthy relatives (Toichi et al, 1999;Valkonen-Korhonen et al, 2003;Bär et al, 2005Bär et al, , 2007Bär et al, , 2010Castro et al, 2009;Chang et al, 2009;Voss et al, 2010). The pattern of an unbalanced ANS (heart rate) in schizophrenic patients and their relatives seem to hallmark a disease-inherent genetic feature of this disease.…”